Vehicle seat with arrangement for resisting loads applied to the seat

ABSTRACT

A vehicle seat including an arrangement for resisting loads applied to the vehicle seat which comprises a seat base and a seat back; said arrangement including a link mechanism connected between the seat back and a support member connected to the vehicle. The link mechanism is arranged to prevent motion of the seat back beyond a predetermined position. There is also provided an adjustable tether arrangement including a tether means, the tether means being arranged to be mounted between the seat back and a vehicle body and the tether means including a tether strap and a retractor mechanism enabling the tether strap to extend or retract in accordance with allowed motion of the vehicle seat.

FIELD OF THE INVENTION

The present invention relates to a vehicle seat which includes anarrangement for resisting loads applied to the vehicle seat, and,particularly, but not exclusively, relates to a vehicle seat includingan integrated seat belt.

BACKGROUND OF THE INVENTION

It is well known in vehicles to have seat belts attached directly to thevehicle and not to the seat. This has some advantages, such as thevehicle provides a solid anchor for the seat belt and therefore goodresistance to application of a load to the seat belt. There are somedisadvantages, however. In order to allow for adjustable reclining ofthe seat, or a change in position of the seat relative to the vehicle aseat belt which is attached to the vehicle will need to be readilyadjustable. Because the position of a seat belt is fixed relative to thevehicle, in some adjusted positions of the seat belt the seat may not bein the ideal position for the user. In general, integrated seat belts(where the seat belts are attached to the seat and not to the vehicle)are considered to be safer than seat belts that are anchored to thevehicle. Further, in some cases it is difficult to anchor a seat belt toa vehicle and the seat belt must be integrated with the seat. Examplesof this include public transport eg. seats on buses that are not nearthe walls of the vehicles. In suspension seats, where the seat issuspended relative to the vehicle for comfort, an integrated seat beltis a safer and more convenient option. Suspension seats are often usedin large vehicles such as trucks and military vehicles. Further, in somecases, legislation requires that seats must have integrated seat belts.

Where a seat is provided with an integrated seat belt, the seat must bearranged to cope with the very high loads that may be applied in theevent of an accident. With lap-sash type or harness type seat belts,where the belt is anchored to an upper portion of the seat back, theseat must be especially strong to resist collapsing when load is appliedby the sash or harness. It is in fact often the case that for some typesof vehicles where particularly large loads may be applied, only lapbelts are provided.

In order to deal with the high loads applied to some seats, it is knownto utilise tether straps which attach the seat frame to the vehicle. Inthis way, at least some of the load applied by the integrated seatbeltcan be transmitted via the seat frame to the vehicle. In the event of anaccident, the tether strap prevents the seat from collapsing or movingunder load. A problem with tether straps is that they are of a fixedlength and require adjustment whenever the position of the seat isadjusted or the seat height is changed. If the tether strap is notreadjusted correctly. This can be dangerous.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the present invention provides avehicle seat arrangement, comprising a seat frame, including a seat baseand a seat back, and a support member being arranged to be mountedrelative to a vehicle proximate the seat back, and a link meansconnected between the support member and the seat back, and beingarranged to prevent motion of the seat back beyond a predeterminedposition.

The link means may be a mechanical link connected between the supportmember and the seat back. The link means is arranged to resist motion ofthe seat frame relative to the support member beyond a predeterminedposition. The link means is preferably strong enough to resist motion ofthe seat back relative to the support member under a load, such as aload that may be applied to the seat back during a vehicle accident.

The vehicle seat arrangement may include an integral seat belt. This maybe a lap and sash arrangement or it may be a harness arrangement. Theseat back may include a seat belt mounting for carrying a sash-type seatbelt.

The support member may form part of a suspension arrangement and maycomprise a frame member supporting a suspension arrangement for the seatframe.

The link means may form or form part of a recliner mechanism arranged tocontrol the reclining of the seat back.

In a preferred embodiment, an advantage of having a strong link mountedbetween a support member (perhaps being part of a suspensionarrangement) which is mounted relative to the vehicle, and the seat backobviates the requirement for any tether arrangement as long as the linkand support member are strong enough to resist loads that may beapplied. The link means is preferably positioned between the seat backand the support member to a position which is remote from a pivotconnection between the seat back and seat base. The further away fromthe pivot connection that the link means is positioned and the closer tothe seat belt mounting point on the seat back, the less strain will beapplied to the link means when load is applied via the seat belt to theseat belt mounting. In one embodiment, the link means is positionedremote from the pivot connect between the seat back and seat base. Inaccordance with a second aspect, the present invention provides avehicle seat arrangement, including a seat frame and a tether means, thetether means being arranged to be mounted between the seat frame and avehicle body and the tether means including a tether strap and aretractor mechanism enabling the tether strap to extend or retract inaccordance with allowed motion of the seat frame.

The allowed motion of the seat frame may be normal motion, such asadjustment of the seat position backwards or forwards with respect tothe vehicle, or the normal up and down motion of a suspension seat.During unusual motion, however, such as may occur when a sudden load isapplied to the seat during an accident, the tether strap does not extendor retract and operates to retain the seat frame with respect to thevehicle body, acting as an anchor. Preferably, the retractor mechanismincludes an inertia reel mechanism, which is arranged to lock whenmotion of the seat frame exceeds a pre-determined inertial threshold.The advantages of having a tether strap which is able to extend andretract during normal motion include the ability to be able to adjustthe position of the seat without having to adjust a fixed length tetherstrap, and also the ability to allow a free range of motion for anysuspension system without having to worry about a fixed length tetherstrap.

In one embodiment, the tether means is height adjustable so that it maycope with corresponding adjustments in seat height whilst maintaining anoptimum anchor point for the seat.

The seat arrangement preferably includes a suspension arrangement whichallows the seat frame to move relative to the vehicle in accordance withthe suspension. The seat frame is preferably supported by the suspensionarrangement which includes a support member mounted relative to thevehicle. In one embodiment, the tether means is mounted at one endtherefore to the support member. Where the tether means is mounted tothe support member, preferably a link means is provided between thesupport member and the seat frame, the link means being arranged toresist motion of the seat frame relative to the support member.Preferably, the link means is arranged to extend to a pre-determinedpoint, to allow some limited motion between the seat frame and thesuspension system, but does not allow motion past the pre-determinedpoint.

The seat frame preferably comprises a seat base and a seat back. Thelink is provided between the seat back and the support member. Thisfacilitates mounting of an integrated lap-sash belt to the seat frame,the mounting point for the top part of the sash belt being high up onthe seat back.

In a modification of this embodiment, the link means is replaced by arecliner mechanism. This obviates the need for a standard reclinermechanism at the intersection of the seat back and the seat base.

In accordance with a third aspect, the present invention provides atether arrangement for anchoring a vehicle seat to a vehicle body, thetether arrangement being arranged to be mounted between the seat andvehicle body and including a tether strap and a retractor mechanismenabling the tether strap to extend or retract in accordance withallowed motion of the seat.

In one embodiment, the tether arrangement is height adjustable.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become apparentfrom the following description of embodiments thereof, by way of exampleonly, with reference to the accompanying drawings, in which;

FIG. 1 is a view from the back and one side of a seat arrangement inaccordance with an embodiment of the present invention;

FIG. 2 is a view from the side of the seat arrangement of FIG. 1;

FIG. 3 is a view from the rear of the seat arrangement of FIG. 1;

FIG. 4 is a further side view of the embodiment of FIG. 1;

FIG. 5 is a side view of a further embodiment of the present invention,and

FIG. 6 is a side view of yet a further embodiment of the presentinvention;

FIG. 7 is a side view of yet a further embodiment of the presentinvention, and

FIG. 8 is a detailed schematic view illustrating a linkage between aseat back and support member.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, a seat arrangement in accordance with anembodiment of the present invention, includes a seat frame 1, which inthis embodiment includes a seat back 2 and seat base 3. The seat framemay be made from any appropriate material, such as metal, using knowntechniques. In the drawings the seat frame 1 is shown without anycovering. It will be appreciated that in use the frame 1 will be coveredby coverings and seat base 3 and seat back 2 cushions. The seatarrangement also includes a tether means, generally designated byreference numeral 4 and which includes a retractor mechanism 5 and atether strap 6. In this embodiment the retractor mechanism 5 is aninertia reel mechanism including a reel on which the tether strap 6winds and unwinds. The inertia reel mechanism may be of standard typeand is not shown here in detail. In this embodiment the tether strap hasone end attached to a mounting 7 on a support member 30 which isarranged to be amounted relative to a vehicle (now shown) in use. Theretractor mechanism 5 is arranged to be mounted to a vehicle body, notshown in these drawings. For example, the retractor mechanism 5 could bemounted to the internal wall of the vehicle or a floor of the vehicle.Note that in an alternative embodiment, the retractor mechanism 5 couldbe mounted to the seat arrangement and the other end of the tether strapcould be mounted to the vehicle, the effect being similar.

In operation, the seat arrangement would be mounted in the vehicle on,for example, rails on the vehicle floor. Rails 8 are shown in thedrawings. These may be different from the rails which are mounted on avehicle floor, but nevertheless are sufficient to illustrate. In thisembodiment the rails mount a support member 30. In this arrangement thesupport member 30 is a frame member of the suspension arrangement (to bedescribed later).

In use, the seat frame 1 may be adjusted in height or forwards orbackwards and the inertia reel mechanism 5 enables the tether belt 6 toextend or retract to adjust to the new position of the seat without itbeing necessary to separately adjust the tether strap 6. Duringapplication of a high load to the seat frame 1, such as in an accident,the inertial threshold of the mechanism 5 is exceeded and tether strap 6anchors the seat frame firmly relative to the vehicle.

In this embodiment, the seat arrangement includes a suspensionarrangement 9. Suspension arrangment 9 is not shown in detail, butincludes a housing 10 mounting a suspension system (not shown). Suchsuspension arrangements are known, however, and they include resilientmeans suspending the seat back 2 and seat base 3 for motion relative tothe rest of the seat arrangement, for comfort of the user. One form ofsuspension arrangement is described in applicant's earlier Australianpatent number 728411.

In this embodiment, the mounting 7 for the tether strap 6 is on a framemember of the suspension arrangement 9.

To constrain motion of the seat back 2 relative to the suspensionarrangement 9, a linkage 11 is provided between the frame member 12 ofthe suspension arrangement and the seat back 2. In this embodiment, thelinkage 11 comprises a “scissors” link comprising two members 13 and 14hinged together at hinge 15. The hinge 15 includes a pin 31 rotablyconnecting reel members 13 and 14 and mounted in passageways 32 in linkmember 14 and corresponding passageway (not shown) in link member 13. Afurther pin 33 seated in passageway 34 in link member 13 mounts the linkmember 13 to the frame member 12. A further pin (not shown) mounts anend of the link member 14 to the seat back 2. The hinged arrangement ofthe link 11 enables normal motion of the seat back 2 and seat base 3relative to the suspension arrangement 9 and also enables the seat backto be reclined using recliner mechanism 16A (which is a conventionalrecliner mechanism). Forward motion of the seat back 2 relative to thesuspension arrangement 9 and therefore the tether strap 6 is constrainedat the limit of the extension of the link 11, however. In the event ofan accident, therefore, where a sudden load is applied to the seat back2, the seat back will not extend past the extent of the linkage 11relative to the suspension arrangement.

Note that other types of linkage than a scissor linkage may be used, eg.strong webbing.

The seat arrangement is provided with an integrated lap/sash seat beltsystem 16. The seat belt system includes a seat belt strap 17, and aninertia reel mechanism 18 mounted to the suspension system frame and asash mounting 19. The sash mounting 19 is at the upper part of the seatback 2 and in the event of an accident a significant amount of leveragewill therefore be applied to the seat back. The linkage 11 is thereforestrong enough to prevent the seat back from breaking away from the seatsuspension, even under the excessive leverage.

Note that in FIG. 4, for clarity the cover strap and seat belt are notshown.

FIG. 5 shows a further embodiment of a suspension seat in accordancewith the present invention. The same reference numerals have been usedfor similar components to the components of FIGS. 1 to 4, and no furtherdescription will be given here of those components. Note that the seatbelt retractor mechanism mounting 18 is not shown in FIG. 5, for thepurposes of clarity, although in operation it would be present.

In the embodiment of FIG. 5, the tether strap 6 is mounted to enableheight adjustment. Height adjustable column 20 mounts at a top endthereof a roller or guide 21 over which the tether 6 is arranged topass. Column 20 can be moved within sleeve 22 and incorporating holes 23in the sleeve and column enable the height of the column 22 be adjustedand retained. The height of the roller or guide 21 can therefore beadjusted in order to adjust the height of the tether strap 6 relative tothe seat frame 1. Note that the tether strap 6 may be connected to thesuspension frame (tether point 7) or directly to the seat back (tetherpoint 7 a).

In some seat arrangements with suspension arrangements, the suspensionarrangement is not at the back of a seat as indicated in thisembodiment, but elsewhere. The linkage 11 may then be mounted to asupport member provided at the back of the seat arrangement.

In a further alternative, the tether strap may be connected directly tothe seat back 2 (as in FIG. 5), thus avoiding the need for the linkage11.

FIG. 6 is a side view of a further embodiment of the present invention.This embodiment is a modification of the embodiment of FIG. 5 and thesame reference numerals have been used in FIG. 6 for equivalentcomponents to those of FIG. 5. The modification relates to the linkagebetween the suspension system 9 and the seat back 2. In this variation,the linkage is replaced by a recliner mechanism 25. The reclinermechanism 25 includes a rotatable handle 26 which can be rotated toadjust the extension of a linkage 27 connecting the suspensionarrangement 9 and seat back 2. Rotation of the handle 26 extends orretracts the linkage 27 to effect reclining of the seat back 2. Therecliner mechanism 25 may be a standard recliner mechanism, withstandard adjustment. The difference here is that the linkage is strongenough to support a load applied to the seat back 2 in the event of anaccident.

In this embodiment there is no need for the conventional reclinermechanism, usually mounted between the seat back and seat base (as inthe FIG. 1 and FIG. 5 embodiments). Instead, this conventional reclinermechanism is replaced by a pivot 28 connecting the seat back 2 and theseat base 3.

The tether mechanism may be fitted with a pre-tension seat beltretractor, similar to that applied in modern vehicles, which operates todraw in the tether strap in collisions.

In the above embodiment, only one tether means is used. More than onetether means can be used to anchor the seat.

In the above embodiment, the seat arrangement includes a suspensionmechanism. It need not do. The tether mechanism may be applied with aconventional, non-suspension, seat.

Yet a further embodiment of the present invention is illustrated in FIG.7. Again, the same reference numerals have been used for equivalentcomponents illustrated in other figures. A further detailed descriptionof these components will not be given here.

In this embodiment, a tether strap is dispensed with. The arrangementrelies on the link means 26 to resist any load applied to the seat back1 by, for example, a load on the seat back 2 applied by the integrallap/sash type seat belt (FIG. 3). The support member 12 and rails 8 aremade strong enough to resist this load.

Either a link 11, such as illustrated in FIGS. 1-5, or a recliner link26 as illustrated in FIG. 6 may be utilised.

FIG. 8 is a schematic detail of an appropriate recliner link mechanism26 which could be utilised in any of the embodiments discussed above asthe link means to connect the seat back to the support member 12. Therecliner mechanism 25 shown includes a hand wheel 26 which actuates anepicyclic gear train, as is known in standard recliner mechanisms ofthis type. An alternative would be to use a lever controlled rackarrangement.

The recliner mechanism 25 is placed remotely from the seat back pivot.Leverage applied by a seat belt having a mounting point at the top ofthe seat back will be less to the linkage 25 than at the pivot point.

Modifications and variations as would be apparent with skilled addresseeand deemed to be within the scope of the present invention.

1. A vehicle suspension seat arrangement, comprising a seat frame,including a seat base and a seat back, and a support member arranged tobe mounted relative to a vehicle proximate the seat back, the seat framebeing suspended on and movable relative to the support member and a linkmeans comprising a first member connected to the support member and asecond member connected to the seat back, the first and second membershinged together and being arranged to prevent motion of the seat backbeyond a predetermined position corresponding to the extension of thefirst member and the second member.
 2. The vehicle seat arrangement inaccordance with claim 1, wherein the link means is a mechanical scissorlink.
 3. The vehicle seat arrangement in accordance with claim 1,wherein the link means includes a recliner mechanism.
 4. The vehicleseat arrangement in accordance with claim 1, wherein the link means isstrong enough to resist motion of the seat frame relative to the supportmember beyond a predetermined position when a load is applied to theseat back such as may be applied by a seat belt mounting of the seatback in a vehicle accident.
 5. The vehicle seat arrangement inaccordance with claim 1, including an integral seat belt.
 6. The vehicleseat arrangement in accordance with claim 1, wherein the link means ispositioned remote from a pivot connection between the seat back and theseat base.